Rotary sanders are used for a wide variety of commercial sanding purposes as well as home use. They are particularly useful in the automotive repair industry, in woodworking and in applications such as manufacture of cultured tile surfaces. These rotary sanders use a circular abrasive disk, i.e. sand paper which is attached to a sanding pad which rotates. There may be a suction device to vacuum off dust as it is formed.
To be effective, the abrasive surface of the sand paper must be pressed against the surface being sanded. This presents no problem for generally flat surfaces as well as exteriorly radiused surfaces. However when an interior radius is encountered, the sanding disks do not function well.
The edge of these sanding disks are circular and tend to cut into the interior radius. Because there is inadequate contact between the sand paper and the radiused surface, it fails to sand the surface as desired. Also when attempting to sand an interior radius, the edge of the sandpaper can be torn up which in turn could lead to destruction of the sanding pad.
These sanding pads themselves are circular in design and generally include a plurality of holes that attach to a vacuum source. The holes are aligned in a circle and can be connected to each other with a circular groove in the center portion of the sanding pad. The sanding disks themselves have a plurality of radially spaced holes which are adapted to align with either the holes or the grooves in the sanding pad. However, they are difficult to apply on the pad and properly align the holes in the disk with the holes in grooves in the pad.
The present invention is premised upon the realization that sanding disks with one edge formed from a plurality of spaced radial protusions will easily sand an inner radius surface.
The present invention comprises a sandpaper disk for a rotary sander which has an edge portion having radially spaced protusions. The sanding disk is designed so these protusions extend beyond the outer edge of the sanding pad and can easily act upon an inwardly radiused surface without gouging the surface or destroying the sandpaper. Preferably the protusions are curved further facilitating contacting inner radiused surface.
Further the present invention is premised on the realization that the sanding disk itself can more easily remove or vacuum dust wherein instead of having a plurality of radially spaced holes, a plurality of space arcuit grooves are employed. The grooves are spaced so that they do not create a radial imbalance in the sanding disk. This greatly facilitates vacuuming of material.